The present invention relates to a waste-ink collecting apparatus for an ink-jet printer, and, more particularly, to a waste-ink collecting apparatus which collects waste inks to be discharged at the time of maintenance of a recording head that ejects ink.
An ordinary ink-jet printer has a recording head so arranged as to face a recording medium which is to be fed in a predetermined direction. The recording head has a plurality of nozzles aligned in a direction approximately perpendicular to the feeding direction of the recording medium. In printing characters or an image on a recording medium, the recording medium is fed at a constant speed in a predetermined direction and ink is selectively ejected from the nozzles of the recording head.
To accomplish high-resolution printing, the nozzles of a recording head are designed to have a very small diameter and are arranged close to one another at a high density. As the nozzles are made narrow, the nozzles are likely to clog with the passage of time. To prevent clogging of the nozzles of the recording head, the nozzles should be cleaned regularly.
In cleaning the nozzles of the recording head, the recording head is driven to discharge foreign matters and gases from the nozzles with a recording medium unfed. At this time, the waste inks discharged from the nozzles is retained in a predetermined ink retainer.
An air-liquid separation chamber is connected to the ink retainer via a waste-ink tube. Connected to the air-liquid separation chamber is a suction pump which generates negative pressure in the chamber. A filter for trapping an ink mist contained in the discharged gas is provided on the air-discharge side of the suction pump.
When the suction pump is driven, negative pressure is generated in the air-liquid separation chamber, causing the waste inks in the ink retainer to flow into the air-liquid separation chamber via the waste-ink tube. The ink mist discharged via the suction pump is trapped by the filter.
The waste inks that have flown into the air-liquid separation chamber are collected in a waste-ink collection tank by a liquid-discharge pump connected to the air-liquid separation chamber. When the waste-ink collection tank becomes full of waste ink, it is separated from a liquid-discharge tube led out from the liquid-discharge side of the liquid-discharge pump and removed.
With the above conventional structure, if a filter with a rough mesh is selected in consideration of the air discharging performance of the suction pump, it is not possible to completely trap the ink mist contained in the discharged air so that a waste ink is discharged in the air.
As the waste-ink collection tank is designed to be removable after it is separated from the liquid-discharge tube, waste inks are likely to leak from the portion where the waste-ink collection tank is connected to the liquid-discharge tube. The conventional structure therefore requires a collection mechanism for collecting the waste inks that have leaked from the connected portion between the tank and the tube.